RESUMO
The scientific publication landscape is changing quickly, with an enormous increase in options and models. Articles can be published in a complex variety of journals that differ in their presentation format (online-only or in-print), editorial organizations that maintain them (commercial and/or society-based), editorial handling (academic or professional editors), editorial board composition (academic or professional), payment options to cover editorial costs (open access or pay-to-read), indexation, visibility, branding, and other aspects. Additionally, online submissions of non-revised versions of manuscripts prior to seeking publication in a peer-reviewed journal (a practice known as pre-printing) are a growing trend in biological sciences. In this changing landscape, researchers in biochemistry and molecular biology must re-think their priorities in terms of scientific output dissemination. The evaluation processes and institutional funding for scientific publications should also be revised accordingly. This article presents the results of discussions within the Department of Biochemistry, University of São Paulo, on this subject.
Assuntos
Bioquímica , Biologia Molecular , Publicações Periódicas como Assunto/estatística & dados numéricos , Editoração/tendências , Pesquisa , Brasil , Humanos , Publicações Periódicas como Assunto/normas , Publicações Periódicas como Assunto/tendênciasRESUMO
The scientific publication landscape is changing quickly, with an enormous increase in options and models. Articles can be published in a complex variety of journals that differ in their presentation format (online-only or in-print), editorial organizations that maintain them (commercial and/or society-based), editorial handling (academic or professional editors), editorial board composition (academic or professional), payment options to cover editorial costs (open access or pay-to-read), indexation, visibility, branding, and other aspects. Additionally, online submissions of non-revised versions of manuscripts prior to seeking publication in a peer-reviewed journal (a practice known as pre-printing) are a growing trend in biological sciences. In this changing landscape, researchers in biochemistry and molecular biology must re-think their priorities in terms of scientific output dissemination. The evaluation processes and institutional funding for scientific publications should also be revised accordingly. This article presents the results of discussions within the Department of Biochemistry, University of São Paulo, on this subject.
Assuntos
Humanos , Publicações Periódicas como Assunto/estatística & dados numéricos , Editoração/tendências , Pesquisa , Bioquímica , Biologia Molecular , Publicações Periódicas como Assunto/normas , Publicações Periódicas como Assunto/tendências , BrasilRESUMO
Intratumoral heterogeneity (ITH) represents an obstacle for cancer diagnosis and treatment, but little is known about its functional role in cancer progression. The A Desintegrin And Metalloproteinase 23 (ADAM23) gene is epigenetically silenced in different types of tumors, and silencing is often associated with advanced disease and metastasis. Here, we show that invasive breast tumors exhibit significant ADAM23-ITH and that this heterogeneity is critical for tumor growth and metastasis. We demonstrate that while loss of ADAM23 expression enhances invasion, it causes a severe proliferative deficiency and is not itself sufficient to trigger metastasis. Rather, we observed that, in ADAM23-heterotypic environments, ADAM23-negative cells promote tumor growth and metastasis by enhancing the proliferation and invasion of adjacent A23-positive cells through the production of LGI4 (Leucine-rich Glioma Inactivated 4) and nitric oxide (NO). Ablation of LGI4 and NO in A23-negative cells significantly attenuates A23-positive cell proliferation and invasion. Our work denotes a driving role of ADAM23-ITH during disease progression, shifting the malignant phenotype from the cellular to the tissue level. Our findings also provide insights for therapeutic intervention, enforcing the need to ascertain ITH to improve cancer diagnosis and therapy.
Assuntos
Proteínas ADAM/metabolismo , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Proteínas da Matriz Extracelular/metabolismo , Óxido Nítrico/metabolismo , Proteínas ADAM/genética , Neoplasias da Mama/genética , Linhagem Celular Tumoral , Proliferação de Células , Metilação de DNA , Epigênese Genética , Proteínas da Matriz Extracelular/genética , Feminino , Inativação Gênica , Humanos , Metástase Neoplásica , Proteínas do Tecido Nervoso , Carga Tumoral , Microambiente TumoralRESUMO
Olfactory neuroblastoma (ONB) is a malignant tumor found in the human nasal cavity. These tumors are rare and poorly characterized at the molecular level. In this study, we asked whether olfactory-specific genes are expressed in ONBs by using reverse-transcriptase-polymerase chain reaction. We found that the olfactory marker protein and the RIC-8B genes, which are specifically expressed in mature olfactory neurons, are expressed in ONBs. Importantly, we also found that ONBs express a large variety of odorant receptor genes, representative of different odorant receptor gene subfamilies. Our results show that the ONBs express genes that are normally expressed in mature olfactory neurons and indicate that they are derived from progenitor or immature cells in the olfactory epithelium and not from a clonal expansion of a single or few mature olfactory neurons.
Assuntos
Estesioneuroblastoma Olfatório/genética , Subunidades alfa Gs de Proteínas de Ligação ao GTP/genética , Neoplasias Nasais/genética , Receptores Odorantes/genética , Estesioneuroblastoma Olfatório/patologia , Subunidades alfa Gs de Proteínas de Ligação ao GTP/biossíntese , Regulação Neoplásica da Expressão Gênica , Humanos , Cavidade Nasal/patologia , Neoplasias Nasais/patologia , Neurônios Receptores Olfatórios/citologia , Neurônios Receptores Olfatórios/metabolismo , Receptores Odorantes/biossíntese , Olfato/genéticaAssuntos
Instinto , Odorantes , Neurônios Receptores Olfatórios , Comportamento Estereotipado , Órgão Vomeronasal , Animais , Feminino , Masculino , Neurônios Receptores Olfatórios/fisiologia , Feromônios/fisiologia , Receptores Odorantes/fisiologia , Órgão Vomeronasal/citologia , Órgão Vomeronasal/fisiologiaRESUMO
The discriminatory capacity of the mammalian olfactory system is such that thousands of volatile chemicals are perceived as having distinct odors. Here we used a combination of calcium imaging and single-cell RT-PCR to identify odorant receptors (ORs) for odorants with related structures but varied odors. We found that one OR recognizes multiple odorants and that one odorant is recognized by multiple ORs, but that different odorants are recognized by different combinations of ORs. Thus, the olfactory system uses a combinatorial receptor coding scheme to encode odor identities. Our studies also indicate that slight alterations in an odorant, or a change in its concentration, can change its "code," potentially explaining how such changes can alter perceived odor quality.
Assuntos
Sinalização do Cálcio , Discriminação Psicológica/fisiologia , Odorantes , Isoformas de Proteínas/fisiologia , Receptores Odorantes/fisiologia , Sequência de Aminoácidos , Animais , Mapeamento Encefálico , Cálcio/análise , Ácidos Carboxílicos/química , Expressão Gênica , Camundongos , Camundongos Endogâmicos BALB C , Modelos Neurológicos , Modelos Psicológicos , Dados de Sequência Molecular , Família Multigênica , Bulbo Olfatório/fisiologia , Bulbo Olfatório/ultraestrutura , Neurônios Receptores Olfatórios/fisiologia , Neurônios Receptores Olfatórios/ultraestrutura , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , RNA Mensageiro/análise , Receptores Odorantes/biossíntese , Receptores Odorantes/química , Receptores Odorantes/classificação , Receptores Odorantes/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Relação Estrutura-AtividadeRESUMO
The contraction of skeletal muscle is regulated by Ca2+ binding to troponin C, which results in an internal reorganization of the interactions within the troponin-tropomyosin complex. Troponin T is necessary for Ca2+-dependent inhibition and activation of actomyosin. Troponin T consists of an extended NH2-terminal domain that interacts with tropomyosin and a globular COOH-terminal domain that interacts with tropomyosin, troponin I, and troponin C. In this study we used recombinant troponin T and troponin I fragments to delimit further the structural and regulatory interactions with the thin filament. Our results show the following: (i) the NH2-terminal region of troponin T activates the actomyosin ATPase in the presence of tropomyosin; (ii) the interaction of the globular domain of troponin T with the thin filament blocks ATPase activation in the absence of Ca2+; and (iii) the COOH-terminal region of the globular domain anchors the troponin C-troponin I binary complex to troponin T through a direct Ca2+-independent interaction with the NH2-terminal region of troponin I. This interaction is required for Ca2+-dependent activation of the actomyosin ATPase activity. Based on these results we propose a refined model for the troponin complex and its interaction with the thin filament.
Assuntos
Miosinas/metabolismo , Troponina C/metabolismo , Troponina I/metabolismo , Troponina/metabolismo , Animais , Sítios de Ligação , Cálcio/metabolismo , Galinhas , Ativação Enzimática , Contração Muscular , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Mutagênese Sítio-Dirigida , Ligação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Troponina/química , Troponina/genética , Troponina TRESUMO
Skeletal muscle contraction is regulated by a complex of five polypeptides which are stably associated with the actin filament. This complex consists of two proteins: troponin with three subunits (TnC; TnI and TnT) and tropomyosin (a dimer of two chains). Using deletion mutants of TnC, TnI and TnT we determined that each of these polypeptides can be divided into at least two domains. One domain is responsible for the regulatory properties of the protein. Its interaction with the other components of the system change upon calcium binding to TnC. A second domain present in each of these proteins is responsible for the stable association of the complex to the actin filament. The interactions among this second set of domains is not influenced by calcium binding to TnC. The structural interactions are: 1) interactions between the C-domain of TnC with the N-domain of TnI; 2) interactions of the N-domain of TnI with the C-terminal domain of TnT and 3) interactions between the N-domain of TnT (T1) and actin/tropomyosin.
Assuntos
Citoesqueleto de Actina/metabolismo , Músculo Esquelético/metabolismo , Troponina/metabolismo , Animais , Dimerização , Modelos Moleculares , Mutagênese Sítio-Dirigida , Conformação Proteica , Deleção de Sequência , Tropomiosina/metabolismo , Troponina/genética , Troponina C/genética , Troponina C/metabolismo , Troponina I/genética , Troponina I/metabolismo , Troponina TRESUMO
The production of multi-subunit proteins of eukaryotic origin in Escherichia coli usually relies on the different subunits being expressed individually and the protein being reassembled in vitro. Here we describe the construction and characterization of plasmids capable of coexpressing the three subunits of chicken skeletal muscle troponin complex in E. coli. We demonstrate that the troponin subunits assembled in the cytoplasm of E. coli cell are fully functional. The troponin complex was purified to homogeneity in high yields. When reconstituted into actin filaments, the complex assembled in vivo was capable of regulating the myosin ATPase with a calcium dependence that was identical to the complex reconstituted in vitro. These results demonstrate that the coexpression of the subunits of a protein complex can prevent the accumulation of denatured proteins in inclusion granules.